All Metal upright bass

I have an old metal ( I think aluminium ) upright bass. It sounds great. I have heard it was made by Conn in the 20's or 40's or something. It originally had a wood grain painted on it, but was removed and now is shiny and metallic. Anybody know anything about these basses? I know there are not that many of 'em out there, I've never seen one. Yes, it is all metal, except for a half round of wood inside a aluminium neck shell which the fingerboard is attached. The tailpiece is wood also.. If you know any history, please email me....I will get a picture on this site soon. Thanks, JBOT